The invention relates to a filter element for the separation of dust particles from a gas flow or air flow. The filter element comprises a number of filter pockets and a main support frame, the open mouth edges of the filter pockets being interconnected to the main support frame and its interconnecting traversing ribs.
Such a filter element typically forms part of a large filtration system which is provided with a number of filter elements for use in, for example, air supply installations for ventilating applications in commercial buildings, plants, industrial installations, and painting booths. One such gas filter element is described in U.S. Pat. No. 4,056,375. In this prior art a number of self-supporting, relatively stiff filter pockets are undetachably connected to a main support frame since these filter pockets are immediately and materially integrated with the edges of the non-woven filter pockets by means of a foaming method.
After utilization, when the filter pockets are saturated with dust particles and have to be replaced, it is a great disadvantage that the main support frame is not reusable and must be destroyed. Not only do the filter pockets have to be replaced, but due to the inherent design of the filter pockets, the integrated main support frames have to be replaced as well. This is environmentally unsatisfactory, because the material of the filter pockets cannot simultaneously be recycled with the material of the main support frame. Moreover, heavily contaminated filter pockets may be considered as falling under chemical refuse for which recycling will not be applicable and for which special regulations for disposition are employed.
Other known filtration systems do not allow for an efficient separation of the raw material, either mechanically or chemically, in such integrated filter pockets from the main support frame so that the reuse of materials by a recycling process is not feasible or practicable.
Another disadvantage of the prior art is related to the voluminous space required for storage and transport respectively because the inflexible shape of the filter element. Particularly, the imbedding of the filter pockets in its main support frame, does not allow for a reduction in volume merely by pressing the sides of adjacent filter pockets together. At the most it will be possible to shelve two filter elements in the prior art, identical in sizes, into each other reversely by making use of the wedged spaces of adjacent stiff filter pockets. Transport and storage costs in such an arrangement are not unduly affected.